These three entities are
really easy to use for your own SPQ levels, the difficult
part is creating the chair for the misc_eastertank
to sit in, but I'll leave that part of it to you :)

1. Make sure that your editor is zoomed
in pretty close with a grid or maybe 8 or so. This
way you can be sure that you line everything up right.
2. Place the misc_eastertank
along the floor.
3. Put the misc_easterchick
so that it's bottom side is aligned with the bottom side
of the misc_eastertank.
4. Now put the misc_easterchick2
in the same place as the misc_easterchick.
The picture below will give you a pretty good idea of what
it will look like in the editor after steps 3 and 4.

It really doesn't get any easier than that. Again,
don't ask me how you make the chair for the misc_eastertank,
that is up to you to design.